Sn Alloy and Graphite Addition to Enhance Initial Coulombic Efficiency and Cycling Stability of SiO Anodes for Li‐Ion Batteries

Abstract

Silicon monoxide (SiO) has aroused increased attention as one of the most promising anodes for high‐energy density Li‐ion batteries. To enhance the initial Coulombic efficiencies (ICE) and cycle stability of SiO‐based anodes, a new facile composition and electrode design strategy have been adapted to fabricate a SiO–Sn–Co/graphite (G) anode. It achieves a unique structure where tiny milled SiO–Sn–Co particles are dispersed among two graphite layers. In this hybrid electrode, Sn–Co alloys promoted Li+ extraction kinetics, and the holistic reversibility of SiO and graphite enhanced the electrical conductivity. The SiO–Sn–Co/G electrode delivered an average ICE of 77.6% and a reversible capacity of 640 mAh g−1 at 800 mA g−1, and the capacity retention was above 98% after 100 cycles, which was much higher than that of the SiO with an ICE of 55.3% and a capacity retention of 50%. These results indicated that this was reliable method to improve the reversibility and cycle ability of the SiO anode. Furthermore, based on its easy and feasible fabrication process, it may provide a suitable choice to combine other alloy anodes with the graphite anode.

Insights into the Effect of SiO Particle Size on the Electrochemical Performance between Half and Full Cells for Li-Ion Batteries

“…In the commercial full-cell system, SiO@C needs to be blended with graphite to improve cycling performance and conductivity for realizing large-scale practical applications. 17,44,45 Before the full-cell tests, the cycling performance of SiO@C blended with graphite was also tested in half cells. As shown in Figure S7, the cycling stabilities of the three samples improve with the addition of graphite.…”

“…Recently, SiO, as one of the Si-based anode materials, has been demonstrated to possess excellent comprehensive electrochemical performance and commercial prospects on a small scale. Compared with Si, lower volume expansion (approximately 200%) and confined Si nanodomains in the matrix are better for long-term cycling stability, promoting SiO to a preeminent status as next-generation anodes for high-energy-density LIBs. − Despite the high reversible capacity and stable cycle performance of SiO, the undesirable irreversible phases, non-negligible volume effect, and low intrinsic conductivity become obstacles to large-scale commercial application. ,− …”

Insight into Reversible Conversion Reactions in SnO2‐Based Anodes for Lithium Storage: A Review

“…Carbonaceous materials with high conductivity are the most commonly used matrix in SnO 2 composite anodes. [108,[109][110][111][112][113] The superior compatibility of the coated carbon on the SnO 2 surface can buffer large volume variation and avoid the agglomeration, growth, and fragmentation of SnO 2 particles, [114][115][116][117][118] thus greatly improving the reversibility of conversion reaction. [119][120][121][122][123] In addition, carbon coating is conducive to repair the surface defects and reduce porosity, thereby enhancing the ICE of SnO 2 electrodes.…”

Revealing the size-dependent electrochemical Li-storage behaviors of SiO-based anodes

“…10,11 There are still some challenges facing SiO anodes, including their low initial coulombic efficiency due to the formation of irreversible products (Li y SiO z and/or Li 2 O), non-negligible volume variation, and low intrinsic conductivity. 10 In this regard, various strategies have been developed to tackle these drawbacks, such as carbon coating, [12][13][14][15] particle downsizing, 16,17 compositing with metal/alloy materials, 18,19 and prelithiation/ magnetization treatments. [20][21][22] For example, Liu demonstrated that graphene-encapsulated SiO can improve the reversible capacity and cycling stability.…”